Gather word-start Information to Aid in Scoring.

chrome/browser/history/in_memory_url_index_cache.proto

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // InMemoryURLIndex caching protocol buffers.
 //
 // At certain times during browser operation, the indexes from the
 // InMemoryURLIndex are written to a disk-based cache using the
 // following protobuf description.
 
@@ skipping 49 matching lines @@
       required int32 typed_count = 3;
       required int64 last_visit = 4;
       required string url = 5;
       optional string title = 6;
     }
 
     required uint32 item_count = 1;
     repeated HistoryInfoMapEntry history_info_map_entry = 2;
   }
 
-  // The timestamp of the cache, used to validate against an
-  // accompanying transaction journal.
+  message WordStartsMapItem {
+    message WordStartsMapEntry {
+      required int64 history_id = 1;
+      repeated int32 url_word_starts = 2 [packed=true];
+      repeated int32 title_word_starts = 3 [packed=true];
+    }
+
+    required uint32 item_count = 1;
+    repeated WordStartsMapEntry word_starts_map_entry = 2;
+  }
+
   required int64 timestamp = 1;
-  required int32 history_item_count = 2;
+  // If there is no version we'll assume version 0.
+  optional int32 version = 2;
+  required int32 history_item_count = 3;
 
-  optional WordListItem word_list = 3;
-  optional WordMapItem word_map = 4;
-  optional CharWordMapItem char_word_map = 5;
-  optional WordIDHistoryMapItem word_id_history_map = 6;
-  optional HistoryInfoMapItem history_info_map = 7;
+  optional WordListItem word_list = 4;
+  optional WordMapItem word_map = 5;
+  optional CharWordMapItem char_word_map = 6;
+  optional WordIDHistoryMapItem word_id_history_map = 7;
+  optional HistoryInfoMapItem history_info_map = 8;
+  optional WordStartsMapItem word_starts_map = 9;
 }